A quantitative assessment of phosphorus forms in some Australian soils
A quantitative assessment of phosphorus forms in some Australian soils
复制标题
DOI：
10.1071/sr10092
复制
发表时间：
2011-03
期刊：
影响因子：
1.6
通讯作者：
A. Doolette;R. Smernik;W. Dougherty
中科院分区：
文献类型：
--
作者：
A. Doolette;R. Smernik;W. Dougherty
溶液 31P 核磁共振 (NMR) 光谱是详细表征土壤有机磷的最常用技术，但尚未广泛应用于澳大利亚土壤。我们使用这种技术研究了 18 种不同的澳大利亚土壤中的土壤磷成分。用氢氧化钠-乙二胺四乙酸 (NaOH-EDTA) 混合物处理土壤，提取出高达 89% 的土壤总磷。在每个 31P NMR 谱中可以识别出多达 15 个清晰解析的共振和一个宽信号。良好解析的共振包括正磷酸盐、α-和β-甘油磷酸盐、植酸盐、5'-单磷酸腺苷和磷酸鲨肌醇的共振，以及正磷酸盐单酯区域中的五个未分配共振和低场（较高 ppm 值）的两个未分配共振。 NaOH-EDTA 提取物中的大部分 31P NMR 信号归属于正磷酸盐，占可提取磷的 37-90%。正磷酸单酯构成了第二大可提取磷库 (7-55%)。最显着的共振是由于植酸盐（占 NaOH-EDTA 可提取总磷的 9%）和 α-和 β-甘油磷酸盐（占 NaOH-EDTA 可提取总磷的 1-5%）造成的。有机磷的大部分（占 NaOH-EDTA 可提取总磷的 2-39%）在单酯 P 区域显示为宽峰；我们认为这是由于在大的“腐殖质”分子中发现了磷。正磷酸二酯（NaOH-EDTA 可提取 P 总量的 1-5%）和焦磷酸酯（NaOH-EDTA 可提取 P 总量的 1-5%）是所有土壤提取物中 P 的次要成分。这些结果表明，大腐殖质分子中的有机磷代表了 NaOH-EDTA 可提取土壤磷的第二丰富形式（仅次于正磷酸盐）。此外，较小的含磷化合物（例如植酸盐）在土壤磷中所占的比例比通常假设的要小得多。
Solution 31P nuclear magnetic resonance (NMR) spectroscopy is the most common technique for the detailed characterisation of soil organic P, but is yet to be applied widely to Australian soils. We investigated the composition of soil P in 18 diverse Australian soils using this technique. Soils were treated with a mixture of sodium hydroxide–ethylenediaminetetra-acetic acid (NaOH-EDTA), which resulted in the extraction of up to 89% of total soil P. It was possible to identify up to 15 well-resolved resonances and one broad signal in each 31P NMR spectrum. The well-resolved resonances included those of orthophosphate, α- and β-glycerophosphate, phytate, adenosine-5′-monosphosphate, and scyllo-inositol phosphate, as well as five unassigned resonances in the monoester region and two unassigned resonances downfield (higher ppm values) of orthophosphate. The majority of 31P NMR signal in the NaOH-EDTA extracts was assigned to orthophosphate, representing 37–90% of extractable P. Orthophosphate monoesters comprised the next largest pool of extractable P (7–55%). The most prominent resonances were due to phytate, which comprised up to 9% of total NaOH-EDTA extractable P, and α- and β-glycerophosphate, which comprised 1–5% of total NaOH-EDTA extractable P. A substantially greater portion of organic P (2–39% of total NaOH-EDTA extractable P) appeared as a broad peak in the monoester P region; we propose that this is due to P found in large, ‘humic’ molecules. Orthophosphate diesters (1–5% of total NaOH-EDTA extractable P) and pyrophosphate (1–5% of total NaOH-EDTA extractable P) were minor components of P in all soil extracts. These results suggest that organic P in large humic molecules represents the second most abundant form of NaOH-EDTA extractable soil P (behind orthophosphate). Furthermore, small P-containing compounds, such as phytate, represent a much smaller proportion of soil P than is commonly assumed.